In a high-frequency circuit, a spurious signal generated in a mixing circuit and a matching circuit is removed by a filter circuit. Such a high-frequency circuit has conventionally been configured as a single module. FIG. 6 shows a conventional high-frequency module. In the conventional high-frequency circuit block, mixing circuit 12 mixes a baseband signal fed from baseband section 31 with a local signal fed from oscillator 41. A spurious signal produced by mixing circuit 12 is attenuated by first filter 13 and second filter 22 of filter circuit 18. A desired high-frequency signal has thus been obtained.
In the prior-art high-frequency module, however, due to the structure configured in one module, a spurious signal produced by matching device 14 connected to the input side of first filter 13 directly goes, without passing through first filter 13, matching device 17, and second filter 22, into matching device 24. In the module, matching device 17 is connected to the output side of first filter 13 and the input side of second filter 22, and matching device 24 is located to the output side of second filter 22.
Therefore, in matching device 24, the spurious signal directly come from matching device 14 has an output level greater than that of the spurious signal given attenuation by first filter 13 and second filter 22, accordingly, the resultant spurious signal cannot maintain a desirable attenuation level. As a result, the output level of the spurious signal fed from the high-frequency module has undesirably increased.